Housing and switch for portable electric device

ABSTRACT

A portable electric tool including a housing and handle rigid therewith. The housing is adapted to have a reversible electric motor disposed therein which drives a reciprocating saw blade supported thereby. An on-off switch for the motor is disposed for actuation by the operator while his hand is on the handle. A motor reversing switch is also provided and is disposed so that it cannot be actuated when the operator&#39;&#39;s hand is in place on the on-off switch.

United States Patent Inventors Thaddeus E. Bednarski Tlmonium; Lewis B.Rohr, Baltimore; Robert D. Harris, Baltimore, all of, Md. 861,715 Sept.29, 1969 June 15, 1971 The Black and Decker Manufacturing CompanyTowson, Md.

Appl. No. Filed Patented Assignee HOUSING AND SWITCH FOR PORTABLEELECTRIC DEVICE 5 Claims, 3 Drawing Figs.

US. Cl. 200/157, v 310/50 lnt.Cl ..H0lh 21/10 [50] Field of Search200/157; 310/50 [56] References Cited UNITE-D STATES BATENTS 2,936,3495/1960 Johnson 200/50 3,511,951 5/1970 Miller 200/157 PrimaryExaminer-D. X. Sliney I Attorneys Leonard Bloom and Joseph R. SlotnikABSTRACT: A portable electric toollincluding a housing and handle rigidtherewith. The housing is adapted to have a reversible electric motordisposed therein which drives a reciprocating saw blade supportedthereby. An on-oiT switch for the motor is disposed for actuation by theoperator while his hand is on the handle. A motor reversing switch isalso provided and is disposed so that it cannot be actuated when theoperators hand is in place on the on-off switch.

PATENTEUJUNISIQYI 3.585.331

. INVENTO 27 Rs THADDEUS E. BEDNARSKI LEWIS H. ROHR HOUSING AND SWITCHFOR PORTABLE ELECTRIC DEVICE SUMMARY OF THE INVENTION The presentinvention is directed to a novel housing and switch construction for aportable electric device, which construction embodies a handle, anon-off switch, and a reversing switch, and which prevents motorreversing when the motor is on. This invention embodies simplicity andreliability in that no mechanical or electrical interlocks are-employedbetween the switches, and is durable and inexpensive in that spatialrelationship between parts rather than extra parts, is relied upon.

Main objects of the present invention, therefore, are to provide a novelhousing and switch construction for a portable, reversible electricdevice which prevents motor reversing when the motor is "on" and withoutthe need for mechanical or elastic interlocks between the on-ofi andreversing switches.

Further important objects are to provide a novel housing and switchconstruction of the above character which requires no extra parts andwhich is easily adaptable for a large variety of devices.

Additional important objects of this invention are to provide a novelconstruction of the above character which is relatively inexpensive tomanufacture, rugged in construction, and reliable in use.

Other objects and advantages of this invention will become more apparentfrom a consideration of the detailed description to follow taken inconjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational viewillustrating a portable electric tool embodying the present invention;

FIG. 2 is a top plan view of FIG. 1, with parts broken away and insection, and illustrating an operators handin position on the device;and

FIG. 3 is a view similar to FIG. 2but showing the operators hand removedfrom the device.

BROAD STATEMENT OF THE INVENTION Broadly described, the presentinvention relates to a portable electric device comprising a housingadapted to have an electric motor disposed therein, a handle rigid withsaid housing and adapted to be grasped by an operator, an on-off switchfor said motor disposed on said handle and adapted to be actuated bysaid operator with his hand on said handle, a reversing switch for saidmotor and having an actuator movable through a path to reverse operationon and off" and for reversing the direction of rotationof said motor,respectively; the improvement in said tool wherein said on-off switchmeans includes a depressibletrigger normally-biased toward an "offposition and being actuated to the on" position only when the operator'shand is in place on the handle, said trigger being constructed to turnsaid on-off switch off when said operator releases his hand therefrom,said reversing switch of said motor, said path being disposed forinterference with said operators hand when the latter is in position onsaid handle to actuate said on-off switch, whereby motor reversing isprevented when said motor is "on".

In another aspect, the present invention relates to a portable electricpower tool of the type having a housing adapted to have an electricmotor disposed therein, a handle adapted to be grasped by the operator,tool means adapted to be driven by said motor, and on-off and reversingswitch means for turning said motor on" and "ofF and for reversing thedirection of rotation of said motor, respectively; the improvement insaid tool wherein said on-off switch means includes a depressibletrigger normally biased toward an off" position and being actuated tothe on" position only when the operators hand is in place on the handle,said trigger being constructed to turn said on-off switch off" when saidoperator releases hishand therefrom, said reversing switch meansincluding a pivoted lever movable past said trigger, said pivoted leverbeing prevented from movement past said trigger byinterference with theoperators hand when in place on said handle.

In still another aspect, the present invention relates to an electricpowered device including a housing, electric motor means within saidhousing, first and second manually operable switches interconnected withsaid motor means and operable to control different operatingcharacteristics thereof, said first switch including manually operablemeans movable through a path for operation thereof, said path beingdisposed for interference with the operators hand when the latter is inposition to actuate said second switch, whereby actuation of .said firstswitch is prevented when said second switch is actuated.

DETAILED DESCRIPTION Referring now more specifically to the drawing, aportable, electric power tool, which is one type of device in which thepresent invention finds use, is illustrated generally at 11 in FIG. 1and is seen to include a motor housing 13 having a gear case 15 suitablysecured thereto. An electric motor (not shown) is disposed within thehousing 13 and is powered from a suitable electric source connectedthereto by a line cord 17. A handle 19 is rigid with the housing andfacilitates easy operator manipulation and control of the tool 11.

The motor (not shown) is connected by a transmission (not shown) to areciprocating slide (not shown) to which a saw blade 21 is adapted to befixed. Since the details of the motor, transmission and slide form nopart of the present invention, they are not illustrated nor describedfurther here. However, for a better understanding thereof, reference maybe made to the copending application of Thaddeus E. Bednarski, Ser. No.745,064, filed July I6, 1968, and owned by the assignee of the presentapplication.

Thus, when the motor is turned on, the blade 21 reciprocates. A shoe 23on the front of the gear case 15 abuts against a workpiece to be cut bythe blade 21 and stabilizes the tool 1 l.

The motor for the tool 11 is adapted to be turned on" by an on-offswitch 24 having a trigger 25 disposed on the handle 19. The switchtrigger 25 is normally biased toward an off position, shown in FIGS. 1and 3, but is movable to an on. position, shown in FIG. 2. Thus, thetrigger switch 25 preferably, but not necessarily, is located adjacentthe top of the handle 19 and is adapted to be grasped and depressed bythe forefinger 26 of an operator with his hand 28 on the bandle 19 (seeFIG. 2). When the operator releases the on-off switch trigger 25, thetool motor turns off."

In addition, a motor reversing switch 26 having a switch lever 27 isprovided on the housing 13. This lever 27 is adapted to be manuallymoved through an arcuate path, illustrated in FIGS. 2 and 3, to reversethe polarity of the tool motor. In the case of a drill, screwdriver,impact wrench, or the like, where the tool output rotates, reversal ofmotor polarity would reverse the direction of rotation of this output.In the particular reciprocal saw illustrated here, the transmissionwhich connects the motor to the blade 21 provides a different bladestroke length and correspondingly a difierent blade speed depending uponwhich direction the motor rotates. Again, reference may be made toapplicant's copending application for a better understanding of thistransmission.

In either case, it will be appreciated that should the motor polarity bereversed .when the motor is on, the surge in current through the motorbrushes can shorten their life considerably. In addition, and moreimportantly, accidental reversal of the motor during motor operation inthe tool 11 results both in a considerable mechanical reaction to theoperator and a dramatic change in the output of the tool 11. Thus, theoperator conceivably could lose control of and drop the tool 11 withresulting injury to himself, or to the tool 11, or both.

In any event, it is important that provision be made that the motor of aportable device of this type cannot be reversed when it is on. In thepast, this generally was accomplished by means of a mechanical orelectrical interlock between the on-off and the reversing switches whichprevents actuation of 5 I disposed such that when the operator'sforefinger 26 is holding the switch trigger 25 depressed and in the onposition, as shown in FIG. 2, this finger is disposed in the path ofmovement of the reversing switch lever 27 so that the latter cannot beactuated, accidentally or otherwise. However, when the operator removeshis forefinger 26 from the switch trigger 25, this trigger 25 returns tothe off" position, shown in FIG. 3. In this position, sufi'icientclearance exists to allow the reversing switch lever 27 to be actuatedand the motor reversed.

It will be appreciated that the present invention effectively preventsmotor reversal while the motor is on without any interlock, mechanical,electrical or otherwise, between the switches 24, 26, or the trigger 25and lever 27. Thus, the danger of mechanical or electrical failure,which would allow the motor to be reversed when it is "on" is virtuallyeliminated. Furthermore, without additional parts, safety is preservedwithout increased cost.

While a preferred embodiment of the present invention has beenillustrated and described above in detail, various additions,substitutions, modifications and omissions may be made thereto.

We claim:

1. A portable electric device comprising a housing adapted to have anelectric motor disposed therein, a handle rigid with said housing andadapted to be grasped by an operator, an onoff switch for said motordisposed on said handle and adapted to be actuated by said operator withhis hand on said handle, a reversing switch for said motor and having anactuator movable through a path to reverse operation of said motor, saidpath being disposed for interference with said operator's hand when thelatter is in position on said handle to actuate said onoff switch,whereby motor reversing is prevented when said motor is "on. g

2. A device as defined in claim 1 wherein said housing and handle definea space through which the fingers of the operators hand extend, saidon-off switch 'having an actuator disposed on said handle and withinsaid space, said reversing switch being disposed on said housing, andsaid path of movement of said reversing switch actuator including atleast a portion within said opening.

3. A device as defined in claim 2 wherein said on-off and reversingswitch actuators are disposed opposite one another, said reversingswitch actuator being movable through an arcuate path past said on-offswitch actuator and being adapted to clear said on-off switch actuator,said on-ofi switch actuator being disposed for actuation by a finger ofthe operatos hand when in position on said handle, the actuating fingerof said operator's hand being positioned in said arcuate path when inposition on said on-off switch actuator.

4. In a portable electric power tool of the type having a housingadapted to have an electric motor disposed therein, a handle adapted tobe grasped by the operator, tool means adapted to be driven by saidmotor, and on-off and reversing switch means for turning said motor onand off and for reversing the direction of rotation of said motor,respectively; the improvementin said tool wherein said on-off switchmeans includes a depressible trigger normally biased toward an offposition and being actuated to the on position only when the operator'shand is in place on the handle, said trigger being constructed to turnsaid on-ofi switch off" when said operator releases his hand therefrom,said reversing switch means including a pivoted lever movable past saidtrigger, said pivoted lever being prevented from movement past saidtrigger by interference with the operator's hand when in place on saidhandle.

5. In an electric powered device including a housing, electric motormeans within said housing, first and second manually operable switchesinterconnected with said motor means and operable to control differentoperating characteristics thereof, said first switch including manuallyoperable means movable through a path for operation thereof, said pathbeing disposed for interference with the operators hand when the latteris in position to actuate said second switch, whereby actuation of saidfirst switch is prevented when said second switch is actuated.

1. A portable electric device comprising a housing adapted to have anelectric motor disposed therein, a handle rigid with said housing andadapted to be grasped by an operator, an on-off switch for said motordisposed on said handle and adapted to be actuated by said operator withhis hand on said handle, a reversing switch for said motor and having anactuator movable through a path to reverse operation of said motor, saidpath being disposed for interference with said operator''s hand when thelatter is in position on said handle to actuate said on-off switch,whereby motor reversing is prevented when said motor is ''''on.''''
 2. Adevice as defined in claim 1 wherein said housing and handle define aspace through which the fingers of the operator''s hand extend, saidon-off switch having an actuator disposed on said handle and within saidspace, said reversing switch being disposed on said housing, and saidpath of movement of said reversing switch actuator including at least aportion within said opening.
 3. A device as defined in claim 2 whereinsaid on-off and reversing switch actuators are disposed opposite oneAnother, said reversing switch actuator being movable through an arcuatepath past said on-off switch actuator and being adapted to clear saidon-off switch actuator, said on-off switch actuator being disposed foractuation by a finger of the operato''s hand when in position on saidhandle, the actuating finger of said operator''s hand being positionedin said arcuate path when in position on said on-off switch actuator. 4.In a portable electric power tool of the type having a housing adaptedto have an electric motor disposed therein, a handle adapted to begrasped by the operator, tool means adapted to be driven by said motor,and on-off and reversing switch means for turning said motor ''''on''''and ''''off'''' and for reversing the direction of rotation of saidmotor, respectively; the improvement in said tool wherein said on-offswitch means includes a depressible trigger normally biased toward an''''off'''' position and being actuated to the ''''on'''' position onlywhen the operator''s hand is in place on the handle, said trigger beingconstructed to turn said on-off switch ''''off'''' when said operatorreleases his hand therefrom, said reversing switch means including apivoted lever movable past said trigger, said pivoted lever beingprevented from movement past said trigger by interference with theoperator''s hand when in place on said handle.
 5. In an electric powereddevice including a housing, electric motor means within said housing,first and second manually operable switches interconnected with saidmotor means and operable to control different operating characteristicsthereof, said first switch including manually operable means movablethrough a path for operation thereof, said path being disposed forinterference with the operator''s hand when the latter is in position toactuate said second switch, whereby actuation of said first switch isprevented when said second switch is actuated.